In recent years, a home energy management system for realizing energy conservation and cost reduction by introducing a power generator and a storage battery in a home and optimizing the operation of household electrical appliances has been proposed.
Moreover, also proposed is a system which changes the operating time of predetermined household electrical appliances to a time block with the highest cost benefit; that is, a time block with the lowest electricity cost.
For example, in Patent Literature 1, the total balance regarding all patterns of combinations of the operating start times of the respective electronic devices is calculated. Subsequently, the combination of the operating start times of the electronic devices which will maximize the total balance; that is, the electronic devices capable of obtaining the greatest profit, is extracted, and the extracted combination is set as a scheduling effect.
Moreover, in Patent Literature 2, the charging schedule of the storage battery is calculated so that charging is performed during a time block in which the unit price of the electricity charge is the most inexpensive, and the discharging schedule of the storage battery is calculated so that discharging is performed during a time block in which the unit price of the electricity charge is the most expensive.
Nevertheless, with a conventional system, there were cases where the operating time of the household electrical appliances was changed to an inconvenient time block for the user and, consequently, the user's convenience was impaired in certain cases.
For example, while it is likely that the scheduling effect obtained in Patent Literature 1 can obtain the greatest profit, it is also likely that the user's convenience will be impaired. Thus, it was difficult to create a schedule capable of achieving both the user's convenience and the user's profit.
Moreover, Patent Literature 2 determines whether to store, in the storage battery, the electric power that was generated by a solar power generator by comparing the unit price of buying and selling of the generated power and the electricity charge unit price for each time block. Thus, no particular consideration was given to the user's convenience, and it was difficult to create a charging schedule and a discharging schedule capable of achieving both the user's convenience and the user's profit.